Automatic device to regulate the vacuum pressure varying the rotation speed of the vacuum pump electrically powered, through the frequency variation of the power supply

ABSTRACT

An automatic device to regulate and maintain stable the vacuum pressure varying the rotation speed of a vacuum pump. The device controls frequency variation of the current that powers its operation motor. The device may be used in installations of machine oerdeñadoras de animales, fixed and portable and other vacuum operated equipment or installations.

BACKGROUND OF THE INVENTION

[0001] 1. Field and Title of the Invention

[0002] The present invention relates to automatic devices to regulateand/or maintain stable the vacuum pressure varying the rotation speed ofthe vacuum pump/s electrically powered, through the controlled frequencyvariation of the current that powers its operation motor, to be usedpreferably in installations of machine oerdeñadoras de animales, fixedand portable and other equipments or installations vacuum operated.

[0003] 2. Technique and Problems to be Sold

[0004] Nowadays, in the majority of the equipments and installations,vacuum operated, the vacuum level regulation is made through automaticvalves whose mechanism is activated by the vacuum of the installationitself. So as the vacuum storage in tanks, for the compensation ofsporadic consumption that may occur, is highly inefficient, a capacityor vacuum flow over the required minimum operating pumps and theirmotors at full operation must be generated.

[0005] This surplus of capacity is compensated making the air comethrough the vacuum regulator valve up to, in the event a vacuum loss inthe installation occurs, the said valve closes automatically saidcompensating entering up to the obtention of the stabilization in thevacuum level, after that it lets the outer air enter again.

[0006] Consecuently, this surplus in the vacuum generation, when onlyrequired to compensate sporadical loss, makes the motor pump group needgreater energy consumption and provoke greater wearing out of themovable pieces, greater maintenance costs, greater noise levels, greaterlubricants consumption, all of them in detriment of the installation.

[0007] For the purposes of a better understanding of the object andscope of this invention, the technique actual in relation to thereferred automatic valves above mentioned is hereafter stated, through abrief description of their construction and functioning through thedrawings (FIG. 1 and 2) that are purely informative regarding the FIGS.3, 4 and 5 concretely referred to the device object of the presentinvention.

[0008]FIG. 1 shows the functioning of a vacuum regulator servo assisted,automatic, pneumatic, conventional, one of them object of the presentinvention that acts regulating the vacuum flow generated excessively bythe vacuum pump.

[0009] The sensor device a, in this case mounted on the superior part ofthe regulator body—sometimes it can be separated—has a chamber 1connected to vacuum system b. by the duct 2 in charge of the detentionof the vacuum variations of it. A compression spring 3, that accordingto the tension registered by an adjustment nut 3′, under a lid 4,determines the level of work of the sensor valve and thus the levelmaintained in the entire system b.

[0010] This sensor device a has a diaphragm 5 that with the springmechanism acts on an obturator 6 that controls the opening of a hole 7of atmospheric air entering, according to the regulation defined by theadjustment level of said spring, to a control chamber 1′ complementaryof said chamber 1, from where, in this arrangement, the air surplus thatthe pump sucks when operating at full operation is controlled, and wherea calibrated hole 1″ of outer air entering from the said chamber to thesystem.

[0011] One part of this complementary chamber 1′ is delimited by adiaphragm 8 joint by the outer edge to an obturator 9 which constitutesthe principal valve c, where this obturator is operatively related to acooperative base of a passage 10 outer air entering to the inlet 11 ofthe pump which has an adequate diameter for the generator flow of saidpump.

[0012] This diaphragm 8 pushed by the spring 12, reacts to the vacuumpressure that the sensor mechanism regulates on the upper face insidechamber 1′, by a balance between air inlets and outlets (illustratedwith+sign because in this case it shows a vacuum increase level)regarding to atmospheric pressure (indicated with small circles) thatacts on external face of the diaphragm 8, as lifting obturator 9 of saidmain valve c opens the exterior air through adequate outlets of theregulator body wall that circles said main valve, enters the systemthrough the said passage 10, to the inlet 11 of the pump, as shown witharrows in FIG. 1, and thus compensate the vacuum level in the systemclearly produced when losses (leaks) disappeared.

[0013]FIG. 2 shows that the sensor mechanism detects a decrease in thevacuum level of system b due to leaks that allow the uncontrolledexterior air entering which automatically decreases vacuum pressure inchamber 1 of sensor mechanism a and thus in the complementary chamber 1′that is to say, on the outer or inner phase of the diaphragm 8 and sothe inner spring 12 overpasses atmospheric pressure (circles) andthrough obturator 9 of said diaphragm closes the passage 10 decreasingthe air entering to the system, so as the pump compensates the vacuumlevel decrease of the system b, taking out the greatest airflow of the .. . (esta ultimo) pump or system b.

[0014] For a solution to the referred problem, electronic devices withelectronic vacuum pressure sensors connected to una electronic devicewhich process the electrical signal of the sensor and converts it in acontrol signal of electrical frequency converter are used. The frequencyconverter acts on the speed of electrical motor of vacuum pumps, so asvarying the frequency or cycles per minute (HZ) the motor speed variesdirectly proportional.

[0015] In this case when the vacuum sensor shows a decrease of vacuumpressure level due to an air entering to the system, the electronicreceives the information from the sensor, processes it and sends acontrol signal to a electrical frequency converter which accelerates theelectrical engine of the vacuum pump, to compensate the system,maintaining the pressure leveled, then it desaccelerates to return tothe former situation of the air entering to the system.

[0016] In this case the surplus of vacuum capacity generatescontinuously when necessary, thus producing energy saving, noisereduction and less components misuse, lubricant use and maintenancecosts.

[0017] So economic and environmental benefits are obtained, but althoughthese systems are efficient they are not spread due to the high costs ofthe sensor conjoint and electronic processor that command the frequencyconverter, even though these converters are serial manufactured devicesand highly spread in the market at a reasonable cost.

[0018] The invention herein allows the replacement of this electronicconjoint of high cost by an automatic pneumatic device and purelyelectromechanical, that allows the speed control of a vacuum motor pumpby means of a conventional frequency converter without using anyelectronic processor.

[0019] The invented device reduces the cost of the control system of thefrequency converter and provides the improvements of the motor pumpspeed according the electronic system hereinabove described, regardingcost savings and environmental improvements.

[0020] Thus, this vacuum regulation system through the pump speedvariation, can be spread in less acquisitive power, with the advantagesdescribed herein.

SUMMARY OF THE INVENTION

[0021] The object of the invention is achieved by means of themodification of a automatic pneumatic vacuum regulator valve, with samefunctioning principle of a conventional servo assisted vacuum regulator,where the direct exterior air inlet to the pump through the main valveis eliminated, and so this main valve with its connection to vacuum ductis also eliminated, adding a auxiliary detector device of the vacuumpressure variations in the interior of its regulator chamber, able totransform in a control electrical signal of a frequency converterintercalated in the supply electrical circuit to the motor, and all ofthem through a conjoint merely electromechanical integrated by commonuse components, very simple at a lower cost.

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0022] For clarity and better understanding of the invention resultingfrom the application of the invented device, the present invention isillustrated by way of example according to some preferred embodiments,wherein:

[0023]FIGS. 1 and 2 show an scheme cross-section view of a vacuum servoassisted regulator of nowadays use, non object of the present invention,as exemplary, the first one shows the automatic reaction under a systempressure increase, whereas the second one shows the same reaction undera pressure decrease

[0024]FIG. 3 shows a schematic view of the automatic regulator vacuuminvented, showing its connections to the frequency converter, whichsupplies the motor of the vacuum pump, all of them according to anexemplary embodiment.

[0025]FIGS. 4 and 5 show partial views of the invented device, shown asFIG. 3, according to other variations of the same embodiment, withdifferent generators of the control signal of the converter, equivalentto the one provided in said example of the last figure.

[0026] In the different Figures the same signs indicate same orcorresponding elements or components.

DESCRIPTION

[0027] The referred automatic vacuum regulator device, object of thepresent invention, as shown in FIG. 3 and as shown and described inFIGS. 1 and 2 and acts controlling and varying the electrical frequencyas a means of instantly adjustment of the rotation speed of the motorand the vacuum pump to the necessary speed to maintain a constant vacuumlevel in the event of changes due to eventual air inlet to the system.

[0028] According to hereinabove mentioned and an exemplary embodimentthe device, has the sensor mechanism applied on its upper edge andconnected to vacuum system b but now only through duct 1. The diaphragm8 of the main valve c is coupled to slider 13 of the potentiometer,variable resistance or rheostat d through arm 14.

[0029] The diaphragm 8 displacement by the effect of pressure variationsin chamber 1, leaves aside the slider varying the resistance that thepotentiometer interlaces through wires 15 in the control circuit of afrequency converter e, powered electrically and whose power outlet 16 isconnected to electric motor f that propulses the vacuum pump 9.

[0030] The potentiometer d is usually powered by a low electricalcurrent generated by the same frequency converter or by an externalsupply.

[0031] When an increase in the vacuum level of system b is detected byduct 2, the sensor mechanism a increases the vacuum pressure in chamber1 and therefore in the outer or inner surface of the diaphragm 8 and theatmospheric pressure overpasses the spring 12 rising the arm 14 andactivating the potentiometer b, varying the electrical resistance in thecircuit of the control signal of the frequency converter e, which hasbeen programmed to react accordingly to this control signal, anddecreasing the cycles in the power of electrical motor f dessaceleratingit and decreasing the rotation speed of the vacuum pump, whose flowdecreases at a necessary one to matain the vacuum level registered bythe regulator sensor through the spring 2 adjustment. The oppositesituation is produced when the regulator mechanism causes the increaseof the motor f cycles, accelerating the vacuum pump up to compensate aloss in the vacuum level detected in the system due to an air entering.

[0032] A possible variation of the system is shown in FIG. 4, where thesaid arm 14 and potentiometer d are replaced by a proximity electronicsensor h, that sends the signal to the frequency converter regarding thediaphragm 8 position, that is to say, the vacuum pressure in chamber 1′.

[0033] Other variety is shown in FIG. 5, where a transducer or pressuresensor i detects the vacuum level change in said control chamber 1′ ofthe diaphragm 8. It is worth mentioned that this variation also workswithout the said diaphragm 8, that can be replaced with a rigid lid toclose chamber 1′, disregarding the use of the spring 9. At last, It isimportant to state that an applicable variation regarding any examplehereinabove mentioned consists of having a calibrated hole 1″ andlocating the obturator 6 of the sensor valve operated by the diaphragm,in relation to hole 7 placed in direct communication with the systemthrough the duct 2.

[0034] While the nature and scope of the present invention have beendescribed and determined, as well as the way of implementing it, weclaim property and exclusive right as follows:

We claim:
 1. Automatic device to regulate vacuum pressure varying therotation speed of the vacuum pump powered electrically by the frequencyvariation of the power supply, wherein it has a chamber connected to thevacuum system by a duct able to detect vacuum pressure variation througha calibrated hole of communication with the said chamber, one part ofwhich is delimitated by a diaphragm subject to the pressure of a springof regulable and joint tension to an obturator which controls a hole ofair inlet to the system according to a regulation predetermined by thespring adjustment, including in operative relation with said chamber, anauxiliary device detector of the pressure variation in the inner of saidchamber and provide them as a control electric signal of a frequencyconverter intercalated in the supply circuit of the Automatic device toregulate vacuum pressure electric motor of pump operation.
 2. Automaticdevice to regulate vacuum pressure, according to claim 1 , wherein thatsaid detector device has a second diaphragm incorporated as a part ofthe said chamber wall and connected exteriorly through a joint arm, rod,or the like, of transmission of it movement to the correspondingregulator of a potentiometer, variable resistance reostat, or the like,intercalado in the control circuit of the frequency converter. 3.Automatic device to regulate vacuum pressure, according to claim 1 ,wherein that said detector device has a second diaphragm incorporated asa part of the said chamber wall and connected exteriorly to themonitoring of a proximity sensor able to detect diaphragm positionchanges and generate control electric signal of the frequency converter.4. Automatic device to regulate vacuum pressure, according to claim 1 ,wherein that said detector device has a sensor pressure transducer orthe like applied on the said chamber, in direct operative relation withthe interior of said chamber